将数据从Angular 窗体发送到spring引导控制器时遇到问题：出现以下错误：warn 15020---[nio-8181-exec-2].c.j.mappingjackson2httpmessageconverter:无法计算类型simple type，class com.biblio.fr.biblio.entite.bookdto：org.springframework.beans.factory.beancreationexception:创建名为“com.biblio.fr.biblio.entite.bookdodeserializer”的bean时出错：bean示例化失败；嵌套异常为org.springframework.beans.beaninstantiationexception:未能示例化[com.biblio.fr.biblio.entite.bookdodeserializer]：未找到默认构造函数；嵌套的异常是java.lang.nosuchmethodexception:com.biblio.fr.biblio.entite.bookdtodeserializer.（）
warn 15020---[nio-8181-exec-2].c.j.mappingjackson2httpmessageconverter:无法评估类型simple type，class com.biblio.fr.biblio.entite.bookdto的jackson反序列化：com.fasterxml.jackson.databind.jsonmappingexception:class com.biblio.fr.biblio.entite.bookdodeserializer没有默认（no arg）构造函数
warn 15020---[nio-8181-exec-2].w.s.m.s.defaulthandlerexceptionresolver:已解析[org.springframework.web.httpmediatypenotsupportedexception:内容类型'application/json；字符集=utf-8'不支持]*
这是我的java代码：

@RequestMapping(value = "/addBook", method = RequestMethod.POST, produces = "application/json")
    @ApiOperation(value = "Add a new Book in the Library", response = BookDTO.class)
    @ApiResponses(value = { @ApiResponse(code = 409, message = "Conflict: the book already exist"),
            @ApiResponse(code = 201, message = "Created: the book is successfully inserted"),
            @ApiResponse(code = 304, message = "Not Modified: the book is unsuccessfully inserted") })
    public ResponseEntity<BookDTO> createNewBook(@RequestBody BookDTO bookDTORequest) {
        // , UriComponentsBuilder uriComponentBuilder
        Book existingBook = bookService.findBookByIsbn(bookDTORequest.getIsbn());
        if (existingBook != null) {
            return new ResponseEntity<BookDTO>(HttpStatus.CONFLICT);
        }
        Book bookRequest = mapBookDTOToBook(bookDTORequest);
        Book book = bookService.saveBook(bookRequest);
        if (book != null && book.getId() != null) {
            BookDTO bookDTO = mapBookToBookDTO(book);
            return new ResponseEntity<BookDTO>(bookDTO, HttpStatus.CREATED);
        }
        return new ResponseEntity<BookDTO>(HttpStatus.NOT_MODIFIED);

    }

    private BookDTO mapBookToBookDTO(Book book) {
        ModelMapper mapper = new ModelMapper();
        BookDTO bookDTO = mapper.map(book, BookDTO.class);
        if (book.getCategory() != null) {
            bookDTO.setCategory(new CategoryDTO(book.getCategory().getCode(), book.getCategory().getLabel()));
        }
        return bookDTO;
    }

@JsonIgnoreProperties(ignoreUnknown = true)
@JsonDeserialize(using = BookDTODeserializer.class)
@Data
@AllArgsConstructors
public class BookDTO implements Comparable<BookDTO> {
    @ApiModelProperty(value = "Book id")
    private Integer id;

    @ApiModelProperty(value = "Book title")
    private String title;

    @ApiModelProperty(value = "Book isbn")
    private String isbn;

    @ApiModelProperty(value = "Book release date by the editor")
    private LocalDate releaseDate;

    @ApiModelProperty(value = "Book register date in the library")
    private LocalDate registerDate;

    @ApiModelProperty(value = "Book total examplaries")
    private Integer totalExamplaries;

    @ApiModelProperty(value = "Book author")
    private String author;

    @ApiModelProperty(value = "Book category")
    private CategoryDTO category;

    @Override
    public int compareTo(BookDTO o) {
        return title.compareToIgnoreCase(o.getTitle());
    }

    public BookDTO() {
        super();
    }

}

@Entity
@Data
@AllArgsConstructors
public class Book {
    private static final long serialVersionUID = 425345L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String title;
    private String author;
    private String publisher;
    private String publicationDate;
    private String language;
    private String category;
    private int numberOfPages;
    private String format;
    private String isbn;
    private double shippingWeight;
    private double listPrice;
    private double ourPrice;
    private boolean active = true;

    @Column(columnDefinition = "text")
    private String description;
    private int inStockNumber;

    @Transient
    private MultipartFile bookImage;
}

@Data
@AllArgsConstructors
@JsonDeserialize(using = CategoryDTODeserializer.class)
public class CategoryDTO implements Comparable<CategoryDTO> {
    public CategoryDTO() {
    }

    public CategoryDTO(String code, String label) {
        super();
        this.code = code;
        this.label = label;
    }

    @ApiModelProperty(value = "Category code")
    private String code;

    @ApiModelProperty(value = "Category label")
    private String label;

}

@Entity
@Table(name = "CATEGORY")
public class Category {
    public Category() {
    }

    public Category(String code, String label) {
        super();
        this.code = code;
        this.label = label;
    }

    private String code;

    private String label;

    @Id
    @Column(name = "CODE")
    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    @Column(name = "LABEL", nullable = false)
    public String getLabel() {
        return label;
    }

    public void setLabel(String label) {
        this.label = label;
    }
}

public class BookDTODeserializer extends StdDeserializer<BookDTO> {

    @Override
    public BookDTO deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        // TODO Auto-generated method stub
        JsonNode node = p.getCodec().readTree(p);
        Integer id = (Integer) ((IntNode) node.get("id")).numberValue();
        String title = node.get("title").asText();
        String isbn = node.get("isbn").asText();
        LocalDate releaseDate = LocalDate.parse(node.get("releaseDate").asText());
        LocalDate registerDate = LocalDate.parse(node.get("registerDate").asText());
        Integer totalExamplaries = (Integer) ((IntNode) node.get("totalExamplaries")).numberValue();
        String author = node.get("author").asText();
        String codeCategory = node.get("code").asText();
        String labelCategory = node.get("label").asText();

        return new BookDTO(id, title, isbn, releaseDate, registerDate, totalExamplaries, author,
                new CategoryDTO(codeCategory, labelCategory));
        // return null;
    }

    public BookDTODeserializer(Class<?> vc) {
        super(vc);
        // TODO Auto-generated constructor stub
    }

    public BookDTODeserializer(JavaType valueType) {
        super(valueType);
        // TODO Auto-generated constructor stub
    }

    public BookDTODeserializer(StdDeserializer<?> src) {
        super(src);
        // TODO Auto-generated constructor stub
    }

}

public class CategoryDTODeserializer extends StdDeserializer<CategoryDTO> {

    @Override
    public CategoryDTO deserialize(JsonParser p, DeserializationContext ctxt)
            throws IOException, JsonProcessingException {
        JsonNode node = p.getCodec().readTree(p);
        String codeCategory = node.get("code").asText();
        String labelCategory = node.get("label").asText();
        return new CategoryDTO(codeCategory, labelCategory);
    }

    public CategoryDTODeserializer(Class<?> vc) {
        super(vc);
        // TODO Auto-generated constructor stub
    }

    public CategoryDTODeserializer(JavaType valueType) {
        super(valueType);
        // TODO Auto-generated constructor stub
    }

    public CategoryDTODeserializer(StdDeserializer<?> src) {
        super(src);
        // TODO Auto-generated constructor stub
    }

}

还有我的Angular 代码

saveBook(book: Book): Observable<Book>{
      let headers = new HttpHeaders();
      headers.append('content-type', 'application/json');
      headers.append('accept', 'application/json');
      return this.http.post<Book>(environment.apiUrl+'/rest/book/api/addBook', book, {headers: headers});
     }

有什么想法吗？